Variable-delivery pump



Oct. 7, 1952 Q H, DENNY Y 2,612,8,39

VARIABLE-DELIVERY PUMP Md; NSMQQM C. H. DENNY VARIABLE-DELIVERY PUMPoct. 7, 1952 SHEETS-SEET 2 Filed Sep\',. 2, 1947 Patented Get. 7, 1952'Carta-n H. Denny, Seattle, iWaslh., assigner. to Webster-Brinkley Co.;Seattle, Wash., a c0rpo' y ration of Washington Application September 2,1947, Serial No`.`77l,764

tory connection, and providing means bywhich, one of the two pistons ofa, pair may be regulated4 at will from substantially zero to full`WorkingI stroke.

It is a further and important object of the invention to provide a pumpfor the purpose described particularly designed in a manner `whichpermits a battery of pumping units to be compactly assembled togetherand driven from va single power shaft common to all, reserving to eachpump, however, complete independence in respect of pumping output.

With the above and other obJects and advantages in View, which willappear and be understood in the course of the following description andclaims, the invention consists in vthe novel 4 Claims. (Cl. 10S-38),

construction and in .the adaptation and comr' bination of parts.hereinafter described and claimed.

In the drawings: n Figure 1 is a view partly in top plan and partly inhorizontal section illustrating `a battery ,of

four pumping units constructed to embodythe preferred teachings of thepresent invention.

Fig. 2 is a vertical sectional of Fig. 1; and Figs. 3, 4 and 5 arefragmentary vertical sectional views on lines 3-3 of Fig. 2, if-4 .ofFig. 2, and 5`5` of Fig. 1, respectively. Y Y

According to the present invention there. is provided a suitably drivenpower shaft lll journaled in bearings ll carried upon the bed plate i2of a machine frame, and either fixedly secured to or made an integralpart of this shaft are one or more concentric hubs 9. Secured, asy

by the bolts E3, to oppositel end faceslo these hubs are eccentrics I4and I5. The mountingvo,

these eccentrics, which are identicaLis such-that the low point of onecoincides with the hghvpoint of the other, and which is to say that `oneeccentric is shifted about the axis of the shaft '180 from the other.

As before stated, each pumping unit'is ycorriprised of a pair ofreciprocating pistons placed one to the front and the other to the rearof a transverse median line taken through the hub,y and there isprovided one such pair of pistons"V at each side of each pair ofeccentrics with the pair at one side being directly opposed to the viewon line 2--2 pair-at' theother iside. One'eccentric opn'eratesv onepiston of each? of the two units while the other eccentric =acts uponthe other piston vofeach saiduniti Inasmuchf as the structural natureofv the'severalpumping units isridentical, it willv suiii'cevto1d`e`st'zribe"indetail only .a vsingle saidunit. "l .J 1I f" Thepistons in question are denoted viandv l1 andxworkwin respectivecylinders, as IS antik-I9; bored from fthe inner end of .a single block2! rigidly bolted to the bedfplate, and also 'provided inthe block `arerelatively deep counter-bores, as 2| and 22'.. Piston vrods'23 and 24,rigid with the pistons, extend axially through the counter.

bores, and maderrigid with the outerA ends .of Y

theserods are forkedv'cro'ss-heads 25fjournale'd for end-wise movementin slide-Ways of a guide-1v block 26, the guide-block occupying*v a,positionv between' the cylinder block andzthedriven'eccenidlyboltedto'thej bed-plate ofwthe machine' frame. Receivedbetween the fork-arms of'thei respective. cross-heads is a`rotatively-journaled roller -21 arranged to trackvupon the relatedec-`V centric, `andf tojyieldingly urge these-rollers into;

In theinstance of one of thetwo counter@ bores,'=the upper wall isslotted longitudinally forA Y the major, part of .'thelength, l'and'received through and more or less closely fitting vthisslot', which Idenote 3i, is an arm formedcasan in-y tegral dependencyof` atraveler-nut 32, the armv having a` iurcate f extremity '33 str'addlingthe piston-rod at the louter side ofthe collar. 30. Functional to thetraveler nut is a feed-screw designated 34 whichffinds a rotary journalatlits two ends 'in bearings 35 and Vlili bolted to .the cylinder block.For turning the feed-screw a-y knurled knob 3l is pinned or."otherwisefixedl'y secured. thereto, and 'acting as a complement g to the Vknobforresisting endwise thrust transmitted from the pistonrodto thetravelernut is a`pinv 38 working in l'a'circumferential'groove of the'yfeed-screw.

Induction and eduction pipes have shown these pipes as connectingone'fwth one cylinder and the other with the o-therucylinder of'fapumpingunit,introducingfto each' said pipe anon-rerum valve; las 42 andIn.' J-rfn traer that. 1 `roth the inductionand the @duction 'pipesW111i for. 'the "sume" are indicated by 4t'- andl lil, respectively,andfI' and having both the induction and the eduction pipes connectthrough non-return valves with..

this manifold. While using simply a ball check as the non-return valvefor the induction'side of` the pump, I find it desirable to employlaspringclosing valve for the eduction side, incorporating a control wheel46 for regulating the pressureof g the spring.

The operation of the pump is as follows:

Assuming that the traveler nut 32 is shifted by operation of the controlknob 31 to bring the nut to the end limit of its travel working towardthe closed end of the slot 3 I, the collar 30 of the piston-rod 23 willbe then responsively retracted to a degree which places theroller 21 ofits crosshead 25 radially at or beyond the outermost compass of theeccentric I4, and the result is to immobilize the .piston I6, thepiston' I'I meanwhile working through its full stroke, in oppositedirections of reciprocation. This working travel draws into the cylinderin each intake stroke a volume of fluid corresponding to the fulldisplacement of the piston, and in the following discharge stroke suchvolume of fluid is expelled to the eduction pipe. This dischargerepresents the maximum pumping capacity of the pump. Now assuming thatit is desired to reduce the output, the operator simply turns thefeed-screw to shift the traveler nut inwardly toward the eccentrics, andthe reduction in output will then correspond to the relative degree `towhich the immobilized piston is now permitted to move as its relatedroller 21 is brought into the operating sphere -of the eccentric I3,this permitted movement counteracting a corresponding travel of theother piston I1 and the pumping efficiency being consequently reduced tothat amount of fluid which the piston I1 will displace in its remainingtravel. Should the traveler now be shifted rearwardly to the full extentof its sliding movement and such, more especially, as to bring the. sameinto the position in which it is shown in Fig. 2, the related crosshead25 will then reciprocate through the full degree of its permitted traveland responsively transmit to the piston I6 a stroke travel exactlycorresponding but converse to the reciprocal movement of the piston I1,the fluid then simply circulating from the one to the other cylinderwith zero pumping output.

-It will be apparent from an inspection of Fig. 1 that each of themultiple pumping units admits of being independently controlled, and asystem such as I have here described hence becomes especiallyadvantageous as applied to operations which call for the simultaneouspumping of a severalty of different fluids for delivery in necessarypredetermined ratios. The fact of the several pumps each having a commonpowering instrumentality and working under identical conditions givespositive assurance that the pumping output, relatively speaking, willremain absolutely constant. y

The invention should be clear from the foregoing `description of mynow-preferred and illustrated embodiment. Modifications may, however,

4 be resorted to without departing from the spirit of the invention, andI accordingly intend that the hereto annexed claims be read with thebroadest scope commensurate with the language used.

What I claim is:

1. In a variable-delivery pump: the combination of a rotary drive shaft;a pair of identical eccentrics iixedly secured in axially spacedrelation upon the drive shaft with the high point of one placed tocoincide with the low point of the other; a pair of identical fluidpumps placed radial to the shaft in side-by-side relation and each.comprising a cylinder and a reciprocally 'acting piston working in thecylinder and with "the pumping chambers of the two cylinders in constantcommunication; a guide-block between the pistons and the eccentrics;piston-rods rigid with the pistons and each carrying a forked cross-headslidably journaled in the guide-block; respective rollers arranged totrack upon the periphery of the eccentrics and journaled for rotarymovement between the fork arms of the cross-heads; springs acting uponthe cross-heads to yieldingly hold the rollers against the eccentrics;and adjustable means acting counter to the thrust of one of said springsand operating upon the piston-rod to serve as a stop for variablylimiting the stroke travel of the rod.

2. The structure of claim l in which the piston-rods are each providedwith a collar arranged to receive'thevthrust of the related spring, andwherein the stop means comprises a feedscrew and a traveller-nut workingupon the feed screw and providing an arm extending into the path oftravel of one of the collars to interrupt the collar as the latter movesby the thrust of the spring from the high to the low point of therelated eccentric.

3. In a variable-delivery pump: a pair of fluid pumps each comprised ofa reciprocally movable piston anda cylinder for the piston andcharacterized in that the pumping chambers of the cylinders are inconstant communication, one of said pistons having a constant stroketravel while the other piston admits to adjustment of its stroke travel;means for imparting reciprocatory movement to said constant travelpiston; means including ya power-driven eccentric and a counter-actingspring for imparting reciprocatory movement to the adjustable-travelpiston, the arrangement; being such that the direction of movement,pumping function considered, is opposite as between the two pistons; andadjustable means acting counter to the thrust of said spring andoperating as a stop for the related y piston variably limiting thestroke travel thereof,

said fluid pumps both having an identical maximum uid displaced.

4. In a variable-delivery pump, in combination: a rotary drive shaft; aneccentric secured upon the drive shaft; a fluid pump placed radial tothe shaft and comprising a cylinder and a reciprocally acting pistonworking in the cylinder; a guide-block betweenv the piston and theeccentric; a piston-rod rigid with vthe piston and carrying a forkedcross-head slidably journaled in the guide-block; a roller arranged totrack upon the periphery of the eccentric and journaled for rotarymovement between the fork arms of the cross-head; a spring acting uponthe crosshead to yieldingly hold the roller against the eccentric;adjustable means acting counter to the thrust of said spring andoperating upon the piston-rod to serve as a stop for variably limit- 5ing the stroke travel of the rod; a second uid REFERENCES GITED y PumpWhich likewise comprises a cylinder and a' The following references areof `record in the reciprocally moving piston working in the cylinme ofthis patent: der and having its pumping chamber in constantcommunication with the pumping chamber of 5 UNITED STATES PATENTS thefirst-named fluid pump; and means acti- Number Name Date vating thepiston of said second-named fluid 27,610 Borden Mar. 27, 1860 pump andso operatively interconnected with the 1,388,780 Stanley Aug. 23, 1 921eccentric as to cause the two pistons to work in 1,502,195 Hicks, JrJuly 22, `1924 timed concert but with the direction 0f mOVel0 1,640,509Lowe Aug. 30, 1927 ment, pumping function considered, being Oppo-2,32'7,787 Heintz --1 Aug. 24, 1943 site as between the two pistons.

CARTAN H. DENNY.

